Semiconductor device, manufacturing method thereof and manufacturing apparatus therefor

Abstract

A semiconductor device having a semiconductor film formed on a substrate, characterized in that the semiconductor film has laterally grown crystal, and at an end portion of the laterally grown crystal, height of surface projection is lower than film thickness of said semiconductor film, is provided.

1 . A semiconductor device having a semiconductor film formed on a substrate, characterized in that the semiconductor film has laterally grown crystal, and at an end portion of the laterally grown crystal, height of surface projection is lower than film thickness of said semiconductor film.  
   
   
       2 . The semiconductor device according to  claim 1 , wherein 
 said laterally grown crystal is formed by irradiating said semiconductor film with laser.    
   
   
       3 . The semiconductor device according to  claim 1 , wherein 
 said laterally grown crystal has crystal growth enlarged by moving stepwise said laser irradiation along a surface direction of the semiconductor film to be continuous from a portion of crystal grown laterally by the laser irradiation, so that the crystal at said portion is turned over.    
   
   
       4 . The semiconductor device according to  claim 2 , wherein 
 the height of surface projection at the end portion of the laterally grown crystal is made lower than film thickness of the semiconductor film by using laser having energy lower than said laser used for forming said laterally grown crystal.    
   
   
       5 . The semiconductor device according to  claim 3 , wherein 
 a laser having energy lower than said laser used for forming said laterally grown crystal is used in the last step of the stepwise laser irradiation of said semiconductor device.    
   
   
       6 . The semiconductor device according to  claim 3 , wherein 
 a laser having energy lower than said laser used for forming said laterally grown crystal is used in last few steps of the stepwise laser irradiation of said semiconductor device.    
   
   
       7 . The semiconductor device according to  claim 3 , wherein 
 a laser having energy lower than said laser used for forming said laterally grown crystal is used at a position of last irradiation of the stepwise laser irradiation of said semiconductor device.    
   
   
       8 . A method of manufacturing a semiconductor device having a semiconductor film formed on a substrate, comprising the steps of: 
 laterally growing crystal in said semiconductor film by irradiating said semiconductor film with laser; and    lowering a height of surface projection at an end portion of said laterally grown crystal to be lower than thickness of said semiconductor film, by irradiating laser having an energy lower than said laser used for forming said laterally grown crystal.    
   
   
       9 . The method of manufacturing a semiconductor device according to  claim 8 , wherein 
 laser irradiation for laterally growing crystal in said semiconductor film is moved stepwise to take over a portion of grown crystal.    
   
   
       10 . The method of manufacturing a semiconductor device according to  claim 9 , wherein 
 the laser having energy lower than said laser used for forming said laterally grown crystal is used in the last step of the stepwise laser irradiation.    
   
   
       11 . The method of manufacturing a semiconductor device according to claim  9 , wherein 
 the laser having energy lower than said laser used for forming said laterally grown crystal is used in last few steps of the stepwise laser irradiation of said semiconductor device.    
   
   
       12 . The method of manufacturing a semiconductor device according to  claim 9 , wherein 
 the laser having energy lower than said laser used for forming said laterally grown crystal is used at a position of last irradiation of the stepwise laser irradiation of said semiconductor device.    
   
   
       13 . The method of manufacturing a semiconductor device according to  claim 8 , wherein 
 amount of energy irradiation is adjusted by moving a position of a lens or a stage, to realize irradiation of laser having energy lower than said laser used for forming said laterally grown crystal.    
   
   
       14 . The method of manufacturing a semiconductor device according to  claim 8 , wherein 
 one of two laser oscillators having the same wavelength is stopped to realize irradiation of laser having energy lower than said laser used for forming said laterally grown crystal.    
   
   
       15 . The method of manufacturing a semiconductor device according to  claim 9 , wherein 
 in stepwise laser irradiation for laterally growing crystal in said semiconductor film, a main laser oscillator having a wavelength easily absorbed in the semiconductor film and a sub laser oscillator having a wavelength easily absorbed in the substrate or the semiconductor film in a melted state are used, and said sub laser oscillator is stopped to realize irradiation of laser having an energy lower than said laser used for forming said laterally grown crystal.    
   
   
       16 . An apparatus for manufacturing a semiconductor device, used for a method of manufacturing the semiconductor device according to  claim 1 , comprising 
 first and second laser oscillators, and a controller for controlling these two oscillators.    
   
   
       17 . The apparatus for manufacturing a semiconductor device according to  claim 16 , wherein ‘energy of laser emitted from the second laser oscillator is lower than energy of laser emitted from the first laser oscillator.  
   
   
       18 . The apparatus for manufacturing a semiconductor device according to  claim 16 , wherein 
 the laser emitted from the first laser oscillator has a wavelength easily absorbed in the semiconductor film, and the laser emitted from the second laser oscillator has a wavelength easily absorbed in the substrate or the semiconductor film in a melted state.    
   
   
       19 . The apparatus for manufacturing a semiconductor device according to  claim 16 , wherein 
 one of said two laser oscillators is stopped to make height of surface projection at an end portion of laterally grown crystal lower than thickness of the semiconductor film.    
   
   
       20 . The apparatus for manufacturing a semiconductor device according to  claim 19 , wherein 
 said laser oscillator that is stopped is the second laser oscillator.